Shredded threads on crank arms

borderraider

Hi

I've crossed the thread on the cranks when trying to fit new pedals, the thread seems to be kind of worn away and I can no longer screw the pedal in. Is it possible to re-'tap' the crank or am i looking at two new crank arms?

Any help much appreciated.

nicklouse

Yes any good bike shop should have the correct kit to fix it.

borderraider

Cheers Nick

So it's likely the bike shop can retap the threads without having to replace the crank arms?

ugo.santalucia

Borderraider wrote:

Cheers Nick

So it's likely the bike shop can retap the threads without having to replace the crank arms?

Yes...

borderraider

Cheers Ugo, I'll take it in.

nicklouse

ugo.santalucia wrote:

Borderraider wrote:

Cheers Nick

So it's likely the bike shop can retap the threads without having to replace the crank arms?

Yes...

we have not said that the shop you go to can, but a good LBS will have the kit and know how.

Monty Dog

Ring and ask them if they can fit a Helicoil insert - if they don't know what you're talking about, find someone who does. It's a 10-15 minute fix with the right kit.

mmacavity

Sometimes , if you are lucky, it is enough just to clean the threads with a tap. But put the tap in from the side with the good remaining thread ie not from the damaged side.
ie not what this guy does:
http://www.ehow.com/video_5773309_re_th ... pedal.html

http://www.highpath.net/
see crank repairs , they charge £25 - £40 to do the job properly with the new thread (oversized) correctly aligned on a milling machine. Then an insert used.

But as mentioned if you just want a quick job done at LBS, then they should be able to do it.
How well the new insert is aligned is just luck.
http://www.amazon.com/Var-Crank-Repair- ... B004YJ2XNA

ricky1980

interesting, can they rethread the crank arm where the arm connections to the axle of the drive side crank?

nicklouse

ricky1980 wrote:

interesting, can they rethread the crank arm where the arm connections to the axle of the drive side crank?

the threads for the crank puller?

no.

mmacavity

Best to ask Chris at Highpath Engineering:
http://www.highpath.net/



"Pedal thread repairs

Stripped, damaged and crooked pedal threads can usually be repaired by installing a new thread insert. The surrounding area will be faced off square.


Extractor thread repairs

I can often retap stripped extractor threads to a larger size and supply an oversize alloy dustcap and extractor tool. I recommend doing both cranks of a pair so that they use the same tools.

(Note: if you can't remove a crank from its axle, send them both to me, still joined together, plus an extra £ 5.00.)


Crank shortening

Please see the Crank shortening page for details.


Tandem cranks

Send me your standard cranks (2 right-hand ones and 1 left-hand one). I will reverse-thread them to turn them into tandem crossover cranks. I can also shorten them at the same time at no extra cost!


Other modifications

Please contact Chris to discuss any other modifications you may require. Examples might be turning a double crank into a track one, or a double crank into a triple one.

Note: I don't straighten bent cranks or repair damaged bottom-bracket tapers."

ricky1980

thanks for that, it's good to know this...in case I mess up another crank!

cycleclinic

If you have trouble finding some one to do it, I have the kit to fit to destroy the old thread and tap a larger thread and fit a threaded bush/helicoil. This is the best fix.